Antifouling of firearms



Patented Nov. 3, 1942 UNITED STATES PATENT OFFl ANTIFOULING F FIREARMS Charles Hardy, Pelham Manor, N. Y., assignor to Hardy Metallurgical Company, New York, N. Y., a corporation of Delaware No Drawing. Application January 9, 1941,

Serial No. 373,809

' Claims.

- invention is concerned with anti-fouling agents for use in firearms and contemplates the use of certain metallic hydrides to reduce fouling of gun barrels by explosion products. More specifically, my invention contemplates the inclu- -sion in a propellant explosive charge of a metallic hydride that decomposes at temperatures attained in the explosion.

- In accordance with my invention, an appropriate metallic hydride, preferably in finely-divided form and in relatively .small proportion as compared to the explosive charge, is disposed in sufflciently intimate relationship to a propellant charge of explosive, preferably nitro-explosive, that the heat of the explosion decomposes the hydride with release of the metal and of hydrogen. These products of the hydride operate to 1 cium, are suitable for use in the practice of my invention. These hydrides are reasonably stable at atmospheric temperatures and pressures i but decompose at temperatures within the range attained when a confined explosive charge is ignited. Thus, calcium hydride, which is a presently preferred example of a material appropriate for use in accordance with my invention, decomposes into calcium and hydrogen at a temperature of about 770 C., which is substantially below the temperature of 2000 C. that may be attained in a chamber in which a nitro-explosive, for example, nitrocellulose, is exploded. The other hydrides mentioned decompose at even lower temperatures but are, in general, less stable than calcium hydride.

The metallic hydride may be incorporated directly into the explosive charge, or it may be separated therefrom by a capsule wall, a wad, or other barrier which keeps the hydride and the explosive from coming in contact with each other prior .to explosion. The imposition of the barrier is a desirable precaution in cases where the explosive employed may react with the particular'hydride at relatively low temperatures or pressures. In other cases, as when calcium hydride is employed as an anti-fouling agent for nitrocellulose or the like, the hydride may be mixed intimately with the powder charge.

Generally speaking, the proportion of hydride to employ will be small, of the order of a few grams per pound of explosive.

The hydrogen released through decomposition of metallic hydrides under the conditions prevailing during the explosion is especially active,

probably because it is in nascent or. atomic state, This hydrogen, as well as the metal derived through decomposition of the hydride, may react with gaseous or solid products of the explosion to reduce corrosion of the gun barrel, or to reduce fouling thereof by solid products.

In any event, the inclusion of a small proportion of-calcium hydride or other suitable hydride in an explosive charge is recommended for its beneficial efiect upon the active life of the gun barrel through reducing corrosion or erosion, or the amount of solids that remain deposited in the barrel.

Calcium hydride, which I prefer to employ, especially ,with nitro-explosives such as nitrocel lulose, is a brittle bluish substance that may be reduced to granular form by ordinary mild crushing. It may be formed in various ways, for example, by passing hydrogen gas in contact .with metallic calcium' at a temperature of about i and particularly calcium hydride, as anti-fouling It is desirable to include a small proportion of the metallic hydride in each explosive charge. Thus, when the charges are disposed in car-- tridges, each cartridge should contain a small proportion of the hydride together with the explosive. Thus, the hydride may be placed at the rear of the cartridge adjacent the primer and separated from the main explosive charge by a fragile wad which disintegrates or decomposes when the explosion occurs and permits contact between the decomposition products of the hydride and those of the explosive. When the explosive charge is contained in powder bags or the like, a capsule containing the hydride may be loaded in the gun breech along with the bagged charge.

The use of decomposable metallic, hydrides,

agents, is especially useful in conjunction with nitro-explosives, particularly nitrocellulose.-

I claim:

1. A propellant explosive charge containing a metallic hydride that decomposes at the temperature of explosion.

2. A propellant explosive charge containing a relatively smallproportion of a metallic hydride that decomposes at the temperature of explosion.

3. A propellant nitro-explosive charge containing a relatively small proportion of a metallic hydride that decomposes at the temperature of explosion.

4. A propellant nitro-explosive charge containing a small proportion of calcium hydride.

5. A propellant explosive charge having incorpore-ted therein a relatively sman proportion of a metallic hydride that decomposes at the temperature of explosion, the hydride being separated Irom the balance of the charge by a barrier which permits contact of the products of ex-- plosion and of the hydride when explosion occurs.

CHARLES HARDY. 

